The present invention is concerned with improvements of equipment of automatic carton closing machines carried by flap-folding and flap-anchoring elevating heads thereof, and of the general types as are illustrated in U.S. Pat. No. Re. 26,440 of Aug. 13, 1968 (and its parent U.S. Pat. No. 3,236,022) and No. 3,496,697 of Feb. 24, 1970. Such improved equipment here of concern, and variations thereof, provide supporting structure immediately beneath the carton top side flaps as the latter of any particular carton being processed through such machine are down-folded inward, with such supporting structure being withdrawable as each is advanced after flap anchoring equipment carried by the head has accomplished its intended purpose. The disclosures of the above-identified U.S. Pat. Nos. Re. 26,440 and 3,496,697 are embodied herein by reference.
It is an object of the present invention to provide in a relatively simple and economical manner such side flap supporting and biasing means on any such carton closing machine elevating head, that is reliable and does not interfere with the operation of flap anchoring equipment carried by such head while actually cooperating with the latter to assure production of efficient flap anchorages.
For such purpose the head-carried flap supporting and biasing means comprises elongated and relatively stiff plate structure that extends laterally along the path of cartons as they are processed through the machine. This plate structure is located by the head which carries it at an elevation above the carton path approximately that of the top of the sidewalls of the carton to be next transported along this path beneath the elevationally-adjustable head. Accordingly, as intended, this head infolds the upstanding leading front and trailing back end top flaps of any such certain carton and then overlays such infolded top end flaps with a relatively stiff foundation for the side top flaps next to be folded down thereover while avoiding extending transversely a distance greater than the widths of the infolded end flaps so as to prevent interfering with the infolding of such side flaps and the desired carton closing. Such supporting foundation for the infolded side flaps serves efficiently to support the latter as they are being anchored by the head-carried flap anchoring equipment while assuring avoidance of any tendency to crush-damage the carton top, particularly if the carton contents fails adequately to support the infolded closing flaps. This infolded side flaps supporting foundation structure extends laterally along a pair of appreciably laterally spaced longitudinal zones flanking opposite sides of a central longitudinal zone of appreciable width of the carton path with such central zone being available for placement and flaps anchorage action. Also, this flap supporting foundation means when of relatively flat and stiff sheet material slips easily from between the infolded top end flaps and the infolded top side flaps after it has served its desired purpose, merely by virtue of advance of the closed carton forward out of the machine.
In a preferred form such flaps-intervening plate structure is a fork having a pair of elongated, transversely-spaced and longitudinally-extending tines of substantially flat sheet material, each located in a path of forward travel of approximately the medial zone of one of the infolded side flaps whereby the transverse space intervening the tines is available for freedom of action therebetween of the flap anchorage equipment and, if desired, the placement there of the flap anchoring means. Desirably such tines may be of lengths appreciably greater than the longest cartons to be processed through the machine.
Another object is to provide such side flaps supporting and anchorage aiding equipment in forms which assure that the overlaying down-folded side flaps are biased firmly down to a lateral plane just above the down-folded end flaps for secure anchorage in such relative positions by the equipment-applied anchoring means. Such biasing means may be in the form of overlaying weighting means, or magnetic means cooperative with the supporting plate structure, or combinations thereof, as well as equivalents which apply the desired force upon the infolded side flaps to stabilize their positions to the transverse plane of the carton top. This is particularly important when the carton is not completely filled for service of the load as a support for the folded flaps at that plane. Otherwise, top-applying rollers will warp the top folded flaps down into the empty head spaces as such cartons are advanced through the flaps anchoring section, which may cause them to tear out the back end of the cartons in passing. In the use of magnetic biasing means the supporting plate structure, such as the fork tines, may be of paramagnetic material with the cooperating magnetic means being either permanent magnets or electromagnets. The attractive force therebetween does not prevent ready intervening insertion of carton flaps therebetween, and then withdrawal by normal carton advance. If desired, when electromagnets are employed their energizing circuits conveniently may be under the control of switch means associated with the machine power supply.
A further object of the invention is to provide, as convenient and economical means for supporting, in a simple manner the magnetic means on and below the head structure, one or more longitudinal shoes of diamagnetic material for arrangement of a plurality of units as the magnetic means in a single or plurality of longitudinal rows above one or more zones of the paramagnetic plate structure.